How to Cut a Tusk Tenon Joint: Timberframe Woodworking Skills

October 05, 2019
Read time: 2 mins

For historical work, joist hangers won't cut it, so turn to traditional woodworking joinery

It is suitable for structural floor systems where framing needs to surround a chimney, or anywhere there needs to be an opening in a structural floor system.

The process begins with a template, especially if you're cutting more than one of these.

Make a template from 3/8 inch MDF

  • Tennon: /6 of the overall height of the timber
  • Tusk is 1/4 of the thickness of the timber.
  • The shoulder for the beveled housing is precisely in line with the tusk. This shoulder prevents the timber from rotating due to cupping or other movements.
  • Mark the timber using the template, cleaning the lines up with a framing square.
  • Cut the lines using a circular saw and a handsaw. (Make sure to cut on the right side of the line.)

Next, cut the mortise and housings for the joint.

  • Sharpen your chisel

At this point in the video, an integrated ad for SkillShare comes in (from 7:38 to 8:27). Skip it if you want to. It will not hurt our feelings.

  • Cut the tenon with a Forstner bit and then remove the excess with a sharp chisel.
  • Use a precision marking gauge to transfer the exact depth of the shoulder to the tenon board.
  • Use a sharp chisel to cut out the housing for the shoulder.
  • Clean the surfaces with a block plane and chisel.

Mark for the wedge

  • Assemble the joint and mark the tenon where it comes through the mortise.
  • Disassemble the joint and mark with a square just inside the line you just made. This will pull the joint tighter.
  • Make a hardwood wedge and then mark the top and bottom shoulders of the wedge's mortise on the tenon.
  • Drill and chop the wedge mortise.

Assemble the joint and pound the wedge in place. That's it — timber technology from our forefathers!


—This video is from Skill Builder, a YouTube channel that focuses on carpentry training.